References of "Guzmán Inostroza, Carlos Felipe"
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See detailExtension of the Gurson model for the LAGAMINE code
Guzmán Inostroza, Carlos Felipe ULg

Report (2014)

Damage and fracture modeling deals with material softening and strain localization, which usu- ally leads to unwanted numerical features like loss of ellipticity of equilibrium equations, bifurcation into ... [more ▼]

Damage and fracture modeling deals with material softening and strain localization, which usu- ally leads to unwanted numerical features like loss of ellipticity of equilibrium equations, bifurcation into a shear band, etc. A first step before dealing with these problems is to have already a stable, accurate integration scheme for the damage model. Here, the numerical integration of an extended version of the Gurson model (comprising plastic anisotropy and mixed isotropic-kinematic hardening) proposed by Ben Bettaieb et al. (2011b), is revisited and further extended to include nucleation, coalescence and shear. The main feature of this scheme is that all the variables are integrated in an implicit way based on the projection algorithm, while the consistent tangent matrix is obtained analytically. A detailed derivation of the equations used to extend the model is presented and a link with the developed subroutine is made. The efficiency of the implementation is assessed by comparing the numerical results from homogeneous cases from those taken from the literature. The results are in good agreement, hence implying that the model can be used in more complex simulations involving heterogeneous strain paths. [less ▲]

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See detailFully implicit integration scheme for the GTN model
Guzmán Inostroza, Carlos Felipe ULg; Habraken, Anne ULg

Poster (2014, May 12)

Fully integration scheme for the GTN model, applied to some shear extensions. The model also comprises Hill type anisotropy and mixed (Isotropic/kinematic) hardening. The consistent tangent matrix is also ... [more ▼]

Fully integration scheme for the GTN model, applied to some shear extensions. The model also comprises Hill type anisotropy and mixed (Isotropic/kinematic) hardening. The consistent tangent matrix is also calculated. [less ▲]

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See detailNumerical Simulation of a Conical Shape Made By Single Point Incremental
Velosa De Sena, José ULg; Guzmán Inostroza, Carlos Felipe ULg; Duchene, Laurent ULg et al

in Incremental sheet forming (2014, January 06)

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See detailMaterial Parameter characterization for the Gurson model
Guzmán Inostroza, Carlos Felipe ULg

Diverse speeche and writing (2013)

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See detailAbout the Lode angle infuence in ductile fracture
Guzmán Inostroza, Carlos Felipe ULg

Report (2013)

Ductile fracture is a local phenomenon and the state of stress and strain in potential fracture locations should be determined [Bai and Wierzbicki, 2008]. In particular, it is known that the stress state ... [more ▼]

Ductile fracture is a local phenomenon and the state of stress and strain in potential fracture locations should be determined [Bai and Wierzbicki, 2008]. In particular, it is known that the stress state affects the growth rate of cavities (See Lassance et al. [2007] for further references). When the stress triaxiality is not enough to describe the stress state, we can use the Lode parameter [Zhang et al., 2001]. Originally proposed by Lode [1926], this parameter includes the second and third invariant of the deviatoric stress tensor. In this report a state of the art is presented showing the influence of this parameter into micro/macro mechanical models and damage development. Different definitions of the Lode angle exists depending on the author, and they are also presented. [less ▲]

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See detailAbout the Gurson model and his extensions
Guzmán Inostroza, Carlos Felipe ULg

Report (2013)

The goal of the damage models is the prediction of fracture during forming processes or structural loading after a progressive deterioration of material properties. From all the types of damage (brittle ... [more ▼]

The goal of the damage models is the prediction of fracture during forming processes or structural loading after a progressive deterioration of material properties. From all the types of damage (brittle, ductile, creep, fatigue,...), we are particularly interested in the ductile damage, which is associated with large plastic deformation in the neighbourhood of crystal defects. The Gurson model belongs to the coupled approach group, and his strong physical roots has allow a great increase of his use during the last 30 years. In this report a general description of this model, the parameters involved and the finite element implementation in the Lagamine FE code are discussed. [less ▲]

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See detailUsing Gmsh as a mesh generator and post-processor for LAGAMINE
Guzmán Inostroza, Carlos Felipe ULg; Mouton, Thibaud ULg; Habraken, Anne ULg

Scientific conference (2013, September 11)

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See detailAdaptive remeshing technique for the single incremental forming simulations using solid-shell elements
Velosa De Sena, José ULg; Guzmán Inostroza, Carlos Felipe ULg; Duchene, Laurent ULg et al

Scientific conference (2013, September 11)

Nowadays, conventional stamping is a well developed process. It is used for large production manufacturing which amortizes the cost of the tools. However, the possibility to use stamping processes for ... [more ▼]

Nowadays, conventional stamping is a well developed process. It is used for large production manufacturing which amortizes the cost of the tools. However, the possibility to use stamping processes for small volume production or prototypes can be still very expensive. As a result, the Single Point Incremental Forming (SPIF) emerges as a new possibility to solve the cost problem in small volume production. It is performed in a rapid and economic way without the need of expensive tooling. Its dieless nature makes the process appropriate for rapid prototypes and highly personalized pieces. Despite the progresses achieved during the last years, simulating SPIF through the Finite Element Method (FEM) continues nevertheless to be a demanding task. The constantly changing contact conditions between the tool and the sheet surface, as well as the nonlinear material model combined with non-monotonic strain paths during the forming process. In consequence, simulation time increases, even using shell hypothesis and simple geometries. Furthermore, the simulation with 3D “brick” elements in general increases the CPU time even more. To overcome this difficulty, an adaptive remeshing technique that was previously developed for the LAGAMINE code for shell elements [1] and afterwards extended to RESS (Reduced Enhanced Solid-Shell) finite element [2]. This allows that a portion of the sheet mesh is dynamically refined only in the tool vicinity, following its motion. Accordingly, this avoids the requirement of initially refined mesh and, consequently, the global CPU time is reduced. The current study will be focused in a benchmark simulation example applied to a component made by SPIF process using adaptive remeshing combined with RESS finite element. [less ▲]

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See detailAccurate Single Point Incremental Forming Simulations using Solid-Shell Elements
Guzmán Inostroza, Carlos Felipe ULg; Sena, José Ilídio; Duchene, Laurent ULg et al

Scientific conference (2013, September 11)

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See detailDamage prediction in incremental forming
Guzmán Inostroza, Carlos Felipe ULg

Diverse speeche and writing (2013)

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See detailNumerical simulation of a pyramid steel sheet formed by single point incremental forming using solid-shell finite elements
Duchene, Laurent ULg; Guzmán Inostroza, Carlos Felipe ULg; Behera, Amar Kumar et al

in Key Engineering Materials [=KEM] (2013)

Single Point Incremental Forming (SPIF) is an interesting manufacturing process due to its dieless nature and its increased formability compared to conventional forming processes. Nevertheless, the ... [more ▼]

Single Point Incremental Forming (SPIF) is an interesting manufacturing process due to its dieless nature and its increased formability compared to conventional forming processes. Nevertheless, the process suffers from large geometric deviations when compared to the original CAD profile. One particular example arises when analyzing a truncated two-slope pyramid. In this paper, a finite element simulation of this geometry is carried out using a newly implemented solid-shell element, which is based on the Enhanced Assumed Strain (EAS) and the Assumed Natural Strain (ANS) techniques. The model predicts the shape of the pyramid very well, correctly representing the springback and the through thickness shear (TTS). Besides, the effects of the finite element mesh refinement, the EAS and ANS techniques on the numerical prediction are presented. It is shown that the EAS modes included in the model have a significant influence on the accuracy of the results. [less ▲]

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See detailExperimental methods for Lode angle characterization in ductile fracture
Guzmán Inostroza, Carlos Felipe ULg

Diverse speeche and writing (2013)

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See detailTowards fracture prediction in single point incremental forming
Guzmán Inostroza, Carlos Felipe ULg; Habraken, Anne ULg

in Key Engineering Materials [=KEM] (2013), 554-557

The stress state in metal forming processes usually implies low values of triaxiality. It is well known that damage models based only on triaxiality fails to capture the damage behavior properly, and ... [more ▼]

The stress state in metal forming processes usually implies low values of triaxiality. It is well known that damage models based only on triaxiality fails to capture the damage behavior properly, and recent articles have stressed the effect of the Lode parameter in describing damage. Moreover, in some process like incremental forming, the through thickness shear could dominate the rupture mechanism making the description, using solely the triaxiality, inaccurate. In this paper, a preliminary study of the stress state is carried over a near-to-failure single point incremental forming (SPIF) formed cone, through finite elements simulations using a newly developed solid-shell element. The results provide a basis for further studies into damage development in SPIF. [less ▲]

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See detailExperimental Characterisation of Damage Occuring during Single Point Incremental Forming of a Ferritic Steel
Mertens, Anne ULg; Guzmán Inostroza, Carlos Felipe ULg; Habraken, Anne ULg et al

Poster (2012, September)

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid ... [more ▼]

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid prototyping and/or small series production [1]. However, inaccuracies in the shape of the processed part and material failure constitute important limiting factors for applications. In the present research, a numerical approach, based on the damage model proposed by Gurson [2], has been chosen to analyse and optimise the process, predict the material rupture and the process limit. From experimental observations of plastic deformation and ductile fracture, damage is related to the nucleation, growth and coalescence of microvoids [3]. Gurson’s model uses the volume fraction of these voids as a main variable. Hence the determination of this value is a key factor for a correct identification and validation of the model. More particularly, the present work focuses on two different methods used to experimentally characterise damage occurring during single point incremental forming of a ferritic steel. Void measurements carried out by optical microscopy combined with image analysis have been compared with porosity values obtained from density measurements based on the Archimedes’ principle [4], so as to assess the feasibility of using this method for a quick characterisation of the damage. [less ▲]

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See detailStudy of the geometrical inaccuracy on a SPIF two-slope pyramid by finite element simulations
Guzmán Inostroza, Carlos Felipe ULg; Gu, Jun; Duflou, Joost et al

in International Journal of Solids and Structures (2012), 49(25), 3594-3604

Single Point Incremental Forming (SPIF) is a recent manufacturing process which can give a symmetrical or asymmetrical shape to an undeformed metal sheet by using a relative small tool. In this article, a ... [more ▼]

Single Point Incremental Forming (SPIF) is a recent manufacturing process which can give a symmetrical or asymmetrical shape to an undeformed metal sheet by using a relative small tool. In this article, a two-slope SPIF pyramid with two different depths, which suffers from large geometric deviations when comparing the intended and final shapes, is studied. The article goal is to detect if these divergences are due to new plastic strain while forming the second angle pyramid by using finite elements simulations. To validate the numerical results, both the shape and the forces are compared with experimental measurements. Then, an analysis of the material state is carried out taking the equivalent plastic strain, von Mises effective stress and yield stress distribution through a cut in the mesh. It is noticed that there is plastic deformation in the center of the pyramid, far from the tool neighbourhood. Also, high values of stresses are observed under the yield stress in other parts of the sheet. As a strong bending behaviour plus membrane tension is found in some sheet elements, these elastic stresses are due to a bending action of the tool. It is concluded that the main shape deviations come from elastic strains due to structural elastic bending, plus a minor contribution of localized springback, as no plastic deformation is observed in the angle change zone. Future developments in toolpath designs should eventually consider these elastic strains in order to achieve the intended geometry. [less ▲]

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See detailEvaluation of the Enhanced Assumed Strain and Assumed Natural Strain in the SSH3D and RESS3 Solid Shell Elements for Single Point Incremental Forming Simulation
Guzmán Inostroza, Carlos Felipe ULg; Ben Bettaieb, Amine ULg; Velosa de Sena, José Ilidio et al

in Key Engineering Materials [=KEM] (2012), 504-506

Single Point Incremental Forming (SPIF) is a recent sheet forming process which can give a symmetrical or asymmetrical shape by using a small tool. Without the need of dies, the SPIF is capable to deal ... [more ▼]

Single Point Incremental Forming (SPIF) is a recent sheet forming process which can give a symmetrical or asymmetrical shape by using a small tool. Without the need of dies, the SPIF is capable to deal with rapid prototyping and small batch productions at low cost. Extensive research from both experimental and numerical sides has been carried out in the last years. Recent developments in the finite element simulations for sheet metal forming have allowed new modeling techniques, such as the Solid Shell elements, which combine the main features of shell hypothesis with a solid-brick element. In this article, two recently developed elements -SSH3D element [1, 2] and RESS3 element [3]- implemented in Lagamine (finite element code developed by the ArGEnCo department of the University of Liège) are explained and evaluated using the SPIF line test. To avoid locking problems, the well-known Enhanced Assumed Strain (EAS) and Assumed Natural Strain (ANS) techniques are used. The influence of the different EAS and ANS parameters are analysed comparing the predicted tool forces and the shape of a transversal cut, at the end of the process. The results show a strong influence of the EAS in the forces prediction, proving that a correct choice is fundamental for an accurate simulation of the SPIF using Solid Shell elements. [less ▲]

Detailed reference viewed: 89 (45 ULg)